From the Guidelines
Cat scratch disease (CSD) caused by Bartonella henselae bacteria can lead to serious complications, and prompt treatment with azithromycin is recommended for severe infections, with a dosing protocol of 500 mg on day 1 followed by 250 mg for 4 additional days for patients weighing ≥45.5 kg, and 10 mg/kg on day 1 and 5 mg/kg for 4 more days for those weighing <45.5 kg, as supported by the Infectious Diseases Society of America guidelines 1.
Key Considerations
- Cat scratches can lead to several complications, including CSD, which is typically characterized by a papule or pustule at the scratch site, followed by lymphadenopathy, and can resolve without treatment in 2-4 months, but may require antibiotics for severe infections 1.
- The disease course varies, but lymphadenopathy generally resolves within 1–6 months, and in about 10% of cases, the nodes suppurate, while extranodal disease develops in ≤2% of cases 1.
- Diagnosis of Bartonella infections may be difficult due to the fastidious nature of the organism, but serological testing, PCR, and a positive Warthin-Starry silver stain of infected lymph node tissue can support the diagnosis 1.
Treatment Recommendations
- Azithromycin is recommended for CSD, with a strong, moderate evidence rating, according to the dosing protocol outlined by the Infectious Diseases Society of America 1.
- Patients with weakened immune systems should be especially vigilant, as they face higher risks of complications from cat scratches, including bacillary angiomatosis, which can occur in individuals with AIDS 1.
- It is essential to seek medical attention if symptoms such as fever, increasing pain, or swollen lymph nodes develop, as prompt treatment can help prevent serious complications 1.
From the Research
Cat Scratch Complications
- Cat scratch disease is an infection caused by Bartonella henselae, which can lead to various complications, including lymphadenitis, Parinaud oculoglandular syndrome, stellate neuroretinitis, persistent fever, hepatosplenic infection, encephalopathy, osteomyelitis, and endocarditis 2.
- Immunocompromised individuals with B. henselae infection may develop more severe complications, such as bacillary angiomatosis, bacillary peliosis, and relapsing bacteremia with fever syndrome 2.
- The disease can present in different forms, including:
- Tender lymphadenopathy
- Fever of unknown origin
- Lymphadenopathy syndrome
- Hepatosplenomegaly
- Meningoencephalitis
- Bacillary angiomatosis in patients with AIDS 3
Treatment and Management
- The majority of cases of cat-scratch disease do not require anti-infective therapy for resolution of infection 2, 4.
- Antibiotic therapy can be considered for patients with severe cat scratch disease, with efficacious options including rifampin, ciprofloxacin, trimethoprim-sulfamethoxazole, and gentamicin sulfate 4, 5.
- Azithromycin has been shown to speed recovery in some cases 2, 3.
- Conservative, symptomatic treatment is recommended for the majority of patients with mild or moderate cat-scratch disease 4.